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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 551 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.?591 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 23 and take away the sum of its digits. What do you get?
  3. 3.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 41 and take away the sum of its digits. What do you get?
  5. 5.1?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 93 and take away the sum of its digits. What do you get?
  7. 7.4?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 98 and take away the sum of its digits. What do you get?
  9. 9.?491 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.11?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.65?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 49 and take away the sum of its digits. What do you get?
  15. 15.?237 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 55 and take away the sum of its digits. What do you get?
  17. 17.?462 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.39? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.597? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?154 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.3?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.46?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 14 and take away the sum of its digits. What do you get?
  24. 24.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.3?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.3?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.80?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.7?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 40 and take away the sum of its digits. What do you get?
  30. 30.Take 38 and take away the sum of its digits. What do you get?
  31. 31.578? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?543 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.5?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.1?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 39 and take away the sum of its digits. What do you get?
  39. 39.50?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.43?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 3
  2. 18
  3. 8
  4. 36
  5. 9
  6. 81
  7. 8
  8. 81
  9. 4
  10. 9
  11. 2
  12. 7
  13. 4
  14. 36
  15. 6
  16. 45
  17. 6
  18. 6
  19. 6
  20. 8
  21. 5
  22. 7
  23. 9
  24. 4
  25. 2
  26. 9
  27. 3
  28. 8
  29. 36
  30. 27
  31. 7
  32. 4
  33. 6
  34. 8
  35. 2
  36. 8
  37. 5
  38. 27
  39. 8
  40. 5

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